This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this core is to provide access to an epifluorescence microscope with characteristics of a confocal. Technical assistance in the design and utilization of the equipment is (currently) provided free of charge to investigators interested in studying cellular transduction and signaling pathways. Observations from studies with fluorescently tagged proteins typically show the steady state distribution of a protein, but they do not directly provide information about the kinetic properties of molecules. Acquisition of a Nikon single molecule imaging system equipped for time lapse photography of single cells while under incubation at 37 degrees C has been purchased and is now fully equipped with Metamorph software and functional for live cell imaging studies.